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community ecology > midterm > Flashcards

midterm Flashcards

1
Q

what is species richness

A

number of species in a defined region

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2
Q

how does species richness respond with increased area

A

it increases

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3
Q

where is species richness the highest

A

tropics

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4
Q

what is a driver

A

factors that may explain changes in biodiversity

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5
Q

what is a predictor

A

environmental variables that can be measured and correlated with diversity back to drivers

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6
Q

what is genetic diversity

A

hoe much genetic variation there is in a population

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7
Q

what is functional diversity

A

component of diversity that influences ecosystem dynamics, stability, productivity, nutrient balance, and other aspects of ecosystem functioning

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8
Q

what is phylogenetic variation

A

how much distinct evolutionary history is present in a community

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9
Q

what is alpha diversity

A

number of species found at a local site

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10
Q

what is gamma diversity

A

measure of species richness in a region

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11
Q

what is beta diversity

A

a measure of the difference in species composition or turnover between two or more habitats or local sites in a region

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12
Q

what is a region

A

large in spatial scale and containing many habitats and communities

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13
Q

what is a biogeographic region / realm

A

biologically and climatically distinct regions at major geographic boundaries

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14
Q

what is a regional species pool

A

species likely to colonize a local community

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15
Q

how does a more uneven distribution of abundance affect alpha and beta

A

alpha decrease

beta increase

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16
Q

how do spatially clumped individuals within a species effect alpha and beta diversity

A

alpha decrease

beta increase

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17
Q

how does a higher gamma diversity effect beta and alpha

A

increase both

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18
Q

how does a smaller plot area effect alpha and beta

A

alpha decrease

beta increase

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19
Q

how does a higher density of individuals influence alpha and beta

A

alpha increase

beta decrease

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20
Q

factors that change alpha and beta diversity

A

how uneven the distribution is

if the individuals of a species are clumped or spatially random

total regional gamma richness

density of individuals across the region

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21
Q

what is a driver

A

factors that may explain patterns in diversity

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22
Q

what is a predictor

A

environmental variables that can be measured and correlated with diversity and related back to drivers

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23
Q

what is a mechanism

A

process that lead to the pattern

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24
Q

what is evapotranspiration

A

the sum of evaporation from the land surface plus transpiration from plants

shows how much primary productivity

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25
Q

what is diversification

A

speciation - extinction = diversification

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26
Q

how does species richness change as area increases

A

it increases

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27
Q

what are the hypotheses of the latitudinal diversity gradient

A
  • null model
  • ecological hypothesis
  • historical hypothesis
  • evolutionary hypothesis
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28
Q

what is the null model hypothesis of ldg

A

mid domain effect: ranges random and more likely to overlap in middle

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29
Q

what is the ecological hypothesis of ldg

A

climate sets limits for species richness

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30
Q

what is the historical hypothesis of ldg

A
  • area: tropics have more area
    - larger areas can support larger populations = less extinction
    - larger areas have more barriers = more speciation

-time integrated area hypothesis: tropics have suffered fewer harsh climatic events so they have had more time to speciate

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31
Q

what is the evolutionary hypothesis of ldg

A
  • climate stability hypothesis: tropical climate is predictable and mild allowing for greater speciation and smaller niches = more species
    while higher latitudes have unpredictable climates creating larger niches = less species = more extinction
  • evolutionary speed theory : higher temperature and solar radiation = more mutations and faster growth rate = faster speciation rate
  • biotic interactions hypothesis: biotic factors have a stronger selective force than abiotic factors
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32
Q

what is tropical niche conservatism

A

tendency of lineages to originate in tropics and to remain tropical due to the relations of climatic niches over evolutionary time

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33
Q

why does species richness increase with larger areas

A

larger areas have more habitats/niches/diversity so can support more species

larger areas can also support more genetic variation, reduce the chances of a catastrophic event from wiping out the populations, larger area= larger target (more colonization)

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34
Q

what is the target effect

A

bigger area= more colonization

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35
Q

what is the rescue effect

A

isolation influences extinction

more colonization/immigrants increase the fitness of an island

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36
Q

what is the small island effect

A

below a certain point species stop obeying the species richness to area relatioonship

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37
Q

what factors effect z

A

island vs mainland: isolation
dispersal distance of taxonomic group
latitude

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38
Q

how does z effected when its on an island vs mainland

A

higher on islands

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39
Q

how is z effected by dispersal ability

A

lower in species with greater ability to disperse

40
Q

how is z effected by ldg

A

higher in tropics

41
Q

what relationship does z have with dispersal abilities

A

inverse 1

42
Q

what are stabilizing mechanisms

A

spatial variantion in environment and resource partitioning

temporal variation

competition - colonization tradeoff

predators

43
Q

what is spatial variation in the environment/ resource partitioning

A

species have a preference for certain habitat/environmental conditions

often the species that preform best in optimal conditions are least tolerant

species can forage in different parts of same area (ex: foraging in different parts of tree)

44
Q

what is temporal variation

A

seasons changing in environment effect the available nutrient levels as well as how they’re dispersed

certain species are better/worse at certain nutrient levels

storage effect

45
Q

what is the storage effect

A

environmental fluctuations effect one species (with lower abundance) disproportionately
though as its density decreases the competition decreases

46
Q

what is the competition- colonization prediction

A

how species that are better at colonizing are less competitive
and more competitive species are slower at colonizing

47
Q

what is a fugitive species

A

good at colonizing but not as competitive

48
Q

how can predators stabilize prey populations

A

preying on most competitive species (ex:starfish example)

prey- switching (ex generalists)

49
Q

what is a gleamer

A

out compete at low nutrient levels

50
Q

what is an opportunist

A

out compete at higher nutrient levels

51
Q

what is interference competition

A

occurs directly between individuals

individual directly alters the resource attaining behaviour of another individual

52
Q

what is exploitative competition

A

indirect

use of resources by one individual decreases amount available for others

53
Q

what is competitive exclusion principle

A

two species with identical niches cannot coexist indefinitely

54
Q

what is the law of limiting similarity

A

the existence of a maximum level of niche overlap to allow for continued coexistence

55
Q

what is interspecific competition

A

competition between individuals of different species

56
Q

what is intraspecific competition

A

competition between individuals of same species

57
Q

when is coexistence possible?

A

when intraspecific competition is greater than interspecific competition

58
Q

what is R*

A

minimum equilibrium resource level required to maintain a population

59
Q

can 2 species coexist if resource levels are constant

A

no, species with lower r* wins

60
Q

is coexistence possible if resource levels fluctuate

A

yes

61
Q

does coexistence require tradeoffs

A

yes

62
Q

what do organisms try to feed on

A

most profitable food source

63
Q

what are more efficient specialists or generalists

A

specialists

64
Q

what is optimal foraging theory

A

predators adjust their behaviour in response to variation in prey abundance

65
Q

What are consumptive effects

A

lethal effects

occur when predator feeds directly on prey

66
Q

what are non-consumptive effects

A

behavioural changes in prey in response to predation

67
Q

what are examples of non consumptive effects

A

changes in morphology
changes in behaviour
changes in life history (ex timing of metamorphosis)
changes in stress levels

68
Q

why do changes in response to prey have tradeoffs

A

investments in defence cannot be used for reproduction

changes in foraging behaviour may have foraging costs

69
Q

what determine how predators influence a community

A

predator preferences and competitive ability of prey

70
Q

what is a functional response

A

change in predation in response to changing prey density

individual response

71
Q

what is a numerical response

A

change in reproductive rate with changing prey density

population response

72
Q

what are faster functional or numerical responses

A

functional

73
Q

what is a type one functional response

A

linear increase in consumption rate as food densities rise until reaching a maximum consumption rate

slope = consumer’s attack rate

74
Q

what is a type 2 functional response

A

rate of prey consumption rises as prey density increases, though eventually plateaus where rate of consumption remains constant, no matter the increase in prey density

reaches saturation gradually unlike type one which is linear

75
Q

what is a type 3 functional response

A

occur when predators increase their activity with increasing prey, eventually plateauing as prey densities start to decline

76
Q

what type of functional response do generalists have

A

type 3

77
Q

what type of functional response do specialist predators have

A

type 2

78
Q

what is a carrying capacity

A

K

maximum population size supported by the available resources in an environment

79
Q

what is a specialist

A

predator that feeds on a single prey type

80
Q

what is a generalist

A

predators that switch between prey types

81
Q

what does Lotka Volterra model assume

A

prey populations grow exponentially
type 1 functional response
predator growth is independent of predator density

82
Q

what does Lotka Volterra model show

A

simplest model describing population dynamics of a single predator species feeding on a single prey species

produces coupled cycles in predator prey relationships but is very unstable

83
Q

what is the rosenzweig MacArthur model

A

incorporates carrying capacity into prey population of Lotka Volterra to make it more realistic type 2 response which makes isocline be humped

84
Q

what does it mean of predator prey intersect is to the left of isocline

A

system changes can result in one or both species going extinct

85
Q

what does it mean of predator prey intersect is to the right of isocline

A

system will return back to equilibrium after deviation

86
Q

what is an aggregative response

A

immigration and emigration rates

87
Q

what is a demographic response

A

reproduction and mortality rates

88
Q

what does aggregative + demographic responses =

A

numerical response

89
Q

what is the paradox of enrichment

A

increasing prey’s carrying capacity will decrease stability of predator prey dynamics

90
Q

when are predator prey systems most stable

A

when predator is inefficient

91
Q

what is a grinnellian niche

A

the habitat requirements that allow a species to persist and reproduce

92
Q

what is a hutchinsonian niche

A

expanded grinellian niche by separating habitat into specific resources
and considered how species interact

93
Q

what is a eltonian niche

A

an animals place in the biotic environment

ex: its relation to food and enemies

94
Q

what is a sequential breakage hypothesis

A

available niche is slowly divided among species as they arrive

95
Q

what is a broken stick model

A

all species arrive at same time and resources are divided randomly

96
Q

what is a geometric series

A

each successive species takes up a fixed fraction of available niche space

community ecology (2 decks)

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